Protocol Online logo
Top : New Forum Archives (2009-): : Protein Expression and Purification

membrane proteins ultrafiltration - (Feb/24/2013 )

Dear friends,

I have a very diluted sample of membrane proteins and i have to concentrate it. Can i use centricons of millipore or not as i have read that membrane proteins are very difficult to retain in their denatured state. is there any other method by which i can safely concentrate my protein sample.




You should be able to concentrate your sample with a centricon. I don't understand your concern about "maintaining their denatured state." If your buffer has high levels of urea or guanididium, it is very unlikely that your protein will refold or aggregate. You may have problems when you try to dialyze the sample or attempt buffer replacement on the centricon to reduce the urea concentration.


Go ahead and try the centricons. Make sure you save the flow-through in case it is not retained (this has happened to me). You can check the flow-through by SDS-PAGE to make sure you didnt lose the sample.